In recent years, use of mobile terminal devices such as mobile telephones or smartphones has become widespread. In particular, in mobile telephones, use of folding-type terminals has become widespread. In smartphones as well, use of foldable terminals has been proposed.
Patent literature 1 discloses a technique regarding a mobile terminal device capable of performing a correct dial operation while preventing damage to a hinge mechanism even when an excessive external force is applied to a transmitter unit opened with respect to a main body unit.
Patent literature 2 discloses a technique related to an electronic device including two screens in consideration of the balance of weights and the design. The electronic device disclosed in Patent literature 2 includes a first main unit having a surface thereof provided with a display panel, a second main unit having a surface thereof provided with a display panel, and a hinge mechanism coupling the first and second main units. Two operation buttons are arranged symmetrical with respect to a center line of the electronic device extending in a direction in which the two screens are arranged.